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-rw-r--r--kernel/cgroup_pids.c77
1 files changed, 20 insertions, 57 deletions
diff --git a/kernel/cgroup_pids.c b/kernel/cgroup_pids.c
index cdd8df4e991c..b50d5a167fda 100644
--- a/kernel/cgroup_pids.c
+++ b/kernel/cgroup_pids.c
@@ -106,7 +106,7 @@ static void pids_uncharge(struct pids_cgroup *pids, int num)
{
struct pids_cgroup *p;
- for (p = pids; p; p = parent_pids(p))
+ for (p = pids; parent_pids(p); p = parent_pids(p))
pids_cancel(p, num);
}
@@ -123,7 +123,7 @@ static void pids_charge(struct pids_cgroup *pids, int num)
{
struct pids_cgroup *p;
- for (p = pids; p; p = parent_pids(p))
+ for (p = pids; parent_pids(p); p = parent_pids(p))
atomic64_add(num, &p->counter);
}
@@ -140,7 +140,7 @@ static int pids_try_charge(struct pids_cgroup *pids, int num)
{
struct pids_cgroup *p, *q;
- for (p = pids; p; p = parent_pids(p)) {
+ for (p = pids; parent_pids(p); p = parent_pids(p)) {
int64_t new = atomic64_add_return(num, &p->counter);
/*
@@ -162,13 +162,13 @@ revert:
return -EAGAIN;
}
-static int pids_can_attach(struct cgroup_subsys_state *css,
- struct cgroup_taskset *tset)
+static int pids_can_attach(struct cgroup_taskset *tset)
{
- struct pids_cgroup *pids = css_pids(css);
struct task_struct *task;
+ struct cgroup_subsys_state *dst_css;
- cgroup_taskset_for_each(task, tset) {
+ cgroup_taskset_for_each(task, dst_css, tset) {
+ struct pids_cgroup *pids = css_pids(dst_css);
struct cgroup_subsys_state *old_css;
struct pids_cgroup *old_pids;
@@ -187,13 +187,13 @@ static int pids_can_attach(struct cgroup_subsys_state *css,
return 0;
}
-static void pids_cancel_attach(struct cgroup_subsys_state *css,
- struct cgroup_taskset *tset)
+static void pids_cancel_attach(struct cgroup_taskset *tset)
{
- struct pids_cgroup *pids = css_pids(css);
struct task_struct *task;
+ struct cgroup_subsys_state *dst_css;
- cgroup_taskset_for_each(task, tset) {
+ cgroup_taskset_for_each(task, dst_css, tset) {
+ struct pids_cgroup *pids = css_pids(dst_css);
struct cgroup_subsys_state *old_css;
struct pids_cgroup *old_pids;
@@ -205,65 +205,28 @@ static void pids_cancel_attach(struct cgroup_subsys_state *css,
}
}
+/*
+ * task_css_check(true) in pids_can_fork() and pids_cancel_fork() relies
+ * on threadgroup_change_begin() held by the copy_process().
+ */
static int pids_can_fork(struct task_struct *task, void **priv_p)
{
struct cgroup_subsys_state *css;
struct pids_cgroup *pids;
- int err;
- /*
- * Use the "current" task_css for the pids subsystem as the tentative
- * css. It is possible we will charge the wrong hierarchy, in which
- * case we will forcefully revert/reapply the charge on the right
- * hierarchy after it is committed to the task proper.
- */
- css = task_get_css(current, pids_cgrp_id);
+ css = task_css_check(current, pids_cgrp_id, true);
pids = css_pids(css);
-
- err = pids_try_charge(pids, 1);
- if (err)
- goto err_css_put;
-
- *priv_p = css;
- return 0;
-
-err_css_put:
- css_put(css);
- return err;
+ return pids_try_charge(pids, 1);
}
static void pids_cancel_fork(struct task_struct *task, void *priv)
{
- struct cgroup_subsys_state *css = priv;
- struct pids_cgroup *pids = css_pids(css);
-
- pids_uncharge(pids, 1);
- css_put(css);
-}
-
-static void pids_fork(struct task_struct *task, void *priv)
-{
struct cgroup_subsys_state *css;
- struct cgroup_subsys_state *old_css = priv;
struct pids_cgroup *pids;
- struct pids_cgroup *old_pids = css_pids(old_css);
- css = task_get_css(task, pids_cgrp_id);
+ css = task_css_check(current, pids_cgrp_id, true);
pids = css_pids(css);
-
- /*
- * If the association has changed, we have to revert and reapply the
- * charge/uncharge on the wrong hierarchy to the current one. Since
- * the association can only change due to an organisation event, its
- * okay for us to ignore the limit in this case.
- */
- if (pids != old_pids) {
- pids_uncharge(old_pids, 1);
- pids_charge(pids, 1);
- }
-
- css_put(css);
- css_put(old_css);
+ pids_uncharge(pids, 1);
}
static void pids_free(struct task_struct *task)
@@ -335,6 +298,7 @@ static struct cftype pids_files[] = {
{
.name = "current",
.read_s64 = pids_current_read,
+ .flags = CFTYPE_NOT_ON_ROOT,
},
{ } /* terminate */
};
@@ -346,7 +310,6 @@ struct cgroup_subsys pids_cgrp_subsys = {
.cancel_attach = pids_cancel_attach,
.can_fork = pids_can_fork,
.cancel_fork = pids_cancel_fork,
- .fork = pids_fork,
.free = pids_free,
.legacy_cftypes = pids_files,
.dfl_cftypes = pids_files,